Ernst eduard martienssen



April 3, 192s.

E. E. MARTIENSSEN DRAINAGE SYSTEM FOR PLAYING GROUNDS Filed April 12.1927 10 y 7 dg o .g5 D

1 gg. @55% ,iQDmoQ E11/wif.- /yd/'ysfen M KW Patented Apr. 3, 1928iUNITED STATES l team PATENT orifice.v

ERNST EDUARD MARTENSSEN, OF HAMBURG, .GERMANY.

DRAINAGE SYSTEM FOR PLAYING GROUNIDS.

Application tiled April 12, 1927, Serial No. 183,220, and in GermanyDecember 29, 1925.

This invention relates to a system conditioning the surface of playinggrounds,

tennis courts and the like having a drainage or foundation layer. Y

Tennis courts as heretofore constructe suffer from the drawback that theupper layer dries up very quickly and is then too dusty. A consequentadditional drawback is rapid wear of the surface, so that frequentrepairs of the upper layer are necessary, involving considerableexpense. To prevent the formation or the rising of dust, it was commonpractice to moisten the ground by sprinkling, but even this involveslabour and cost.

These drawbacks result from the endeavour to lead away the rain water asquickly as possible, so as to keep the upper layer or surface free fromwater. The leading oif of the rain water is either effected by incliningthe court and conducting the water from the upper surface into a drain,or by giving the water an opportunity to infiltrate to a greater depth;also both expedients have been adopted concomitantly. It is true thateven after heavy rain quick drying up of the ground has been insured,but the drying is found to be so rapid and complete that formation ofdust on the upper layer is an inevitable consequence.

The object of the present invention is to secure a permanently correctcondition of playing grounds or courts and above all to prevent fulldrying up of the covering or surface layer, which is liable to cause thedevelopment of dust.

wWith this object, according to the invention, the intermediate carryingor foundation layer between the covering layer and the natural orartificial impermeable layer is so constructed or so conditioned that itis adapted to take up a certain amount of water and to hold it for aconsiderable time. This draining foundation layer, owing to its contentsof water, automatically gives up moisture to the covering layer at sucha rate that the latter cannot dry up to such an extent as to occasionthe development of loose dust.

In order to promote the transmission of moisture to the covering layerand'in order to regulate the amount of moisture Within the layer in casecontinued drought or frequent heavy rains should influence the conditionof the playing ground there is provided a sluice valve or otherregulator for controlling the water running off the carryV ing layer.This valve serves as a means of controlling the moistness of the playinglduring dry weather, while the playing ground can be kept in such acondition that it may be used in continued wet weather by fully openingthe valve.

Tn the accompanying drawing Figs. l and 2 illustrate two embodiments ofthe invention.

In both constructions shown the playing ground consists of the coveringlayer a made of anymaterial known heretofore in usual manner, theimpermeable layer Z) and the foundation layer c disposed between the twofirst named layers. The impermeable layer may be natural if the soilconsists of clay. The foundation layer c may be composed of broken upbricks, the intermediate spaces or interstices being filled up lwithbrick powder or even better with kieselguhr, or ashes either in a drystate or by the aid of water. The broken-up bricks form the carryingmeans, while the brick powder or kieselguhr on account of itswater-absorbing capacity serves for taking up and giving oli' themoisture to the covering layer a.

Tn the construction .shown in Fig. l the foundation layer is providedwith a plurality of drain pipes c having a certain amount of slope andconnected with one an other, one of them leadingv into a vertical drainpipe f; In front ofthe outlet is provided a sluice valve g, as the casemay be, which prevents or limits or allows the runningoff of Water takenup by the drain pipes 6.

The tennis court shown in Fig. 2 has an inclined impermeable layer Z).The inclination is greatest near the edge, and at this place is arrangedthe vertical drain pipe having a branch L open to the foundation layerc. The valve g is arranged in this branch pipe.

ln both cases by the aid of the valve g the amount of moisture or waterwithin the foundation layer o may be regulated at will.

T claim z- 1. A conditioning system for hard tennis courts comprising` alowermost impermeable layer, the playing surface', and an intermediatelayer in contact with said surface and said impermeable layer, saidintermediate layer being constructed of such material as to take up andretain Water draining through the surface layer, and automatically tomaintain a rate of moisture exchange with the surface layer when thelatter becomes drier than the adjacent part of the intermediate layer,and means Varying the level of Water in said intermediate layer forvarying the rate et moisture exchange.

2. A conditioningsystem for hard tennis Courts comprisinga lowermostimpermeable layer, the playing surface, and an intermediatelayer inContact with said surface and said impermeable layer, said intermediatelayer being constructed of such material as to take up and retain Waterdrained through the surface layer, and automatically to main- 'tain a'ra-te ont moisture exchange with the surface layer when the latterbecomes drier than the adjacent part of the intermediate y layer, andmeans varying the level of Water in said intermediate layer for Varyingthe rate'oit moisture exchange, said means coniprising a drain pipe andsuitable Valve arranged near the lower regions of said intermediatelayer. Y

In testimony whereof I have signed my name to this specification.

ERNST EDUARD MARTIENSSEN. Y

